Quantum signatures of gravity from superpositions of primordial massive particles

Gowtham Amirthya Neppoleon, Aditya Iyer, Vlatko Vedral, and Yi Wang
Phys. Rev. D 105, 043505 – Published 3 February 2022

Abstract

We study the superposition of primordial massive particles and compute the associated decoherence time scale in the radiation dominated Universe. We observe that for lighter primordial particles with masses up to 107kg, the corresponding decoherence timescale is significantly larger than the age of the observable Universe, demonstrating that a primordial particle would persist in a pure quantum state, with its wave function spreading freely. For heavier particles, they can still be in a quantum state while their position uncertainties are limited by the wavelength of background photons. We then discuss three observational signatures that may arise from a quantum superposition of primordial particles such as primordial black holes and other heavy dark matter candidates, namely, interference effects due to superpositions of the metric, transition lines in the gravitational wave spectrum due to gravitationally bound states indicating the existence of gravitons, and witnesses of quantum entanglement between massive particles and of the gravitational field.

  • Figure
  • Received 3 November 2021
  • Accepted 18 January 2022

DOI:https://doi.org/10.1103/PhysRevD.105.043505

© 2022 American Physical Society

Physics Subject Headings (PhySH)

Gravitation, Cosmology & AstrophysicsQuantum Information, Science & Technology

Authors & Affiliations

Gowtham Amirthya Neppoleon1,2,*, Aditya Iyer3,†, Vlatko Vedral3,4,5,‡, and Yi Wang1,2,§

  • 1Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People’s Republic of China
  • 2The HKUST Jockey Club Institute for Advanced Study, Clear Water Bay, Kowloon, Hong Kong, People’s Republic of China
  • 3Townsend Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
  • 4Centre for Quantum Technologies, National University of Singapore, Block S15, 3 Science Drive 2, Singapore, Singapore
  • 5Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore

  • *ganeppoleon@connect.ust.hk
  • aditya.iyer@physics.ox.ac.uk
  • vlatko.vedral@physics.ox.ac.uk
  • §phyw@ust.hk

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Issue

Vol. 105, Iss. 4 — 15 February 2022

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